But keepers at the zoo’s Meet the Monkeys walk-through exhibit have taken to training the 18 cheeky specimens not to be so light-fingered, giving them sunglasses with bitter apple smeared on them as a deterrent.

Pretty in pink: Cheeky monkey

The creatures are drawn to the glare reflecting off the glasses’ lenses – but it’s not the first time their light-fingered skills have surfaced.

Four years ago, keepers had to train them to stop pinching visitors’ mobile phones.

‘They love to see their reflection in the lenses,’ keeper Kate Sanders said of the primates’ current predilection. ‘They find that fascinating sometimes.

‘They’re just a bit cheeky really, especially the young ones – they love the glasses the most.’